C3 Plants, Notably Trees, Tend to Have

C3 plants, notably trees, tend to have:

A) a lower ¹³C signal than C4 plants
B) a higher ¹³C signal than C4 plants
C) a higher ¹⁴C concentration and therefore appear to be younger than C4 plants
D) a lower ¹⁴C concentration and therefore appear to be older than C4 plants